Electronic devices come in many shapes and sizes. One type of electronic device can be formed by mounting electronic device components on a substrate. Some substrates can be quite small, i.e. credit card-size or less, such that the resultant device formed thereon is itself quite small. There is generally, within the industry, an emphasis on decreasing overall device dimensions while increasing the overall performance and/or capabilities of a device. Such industry focus presents challenges regarding, among other things, providing a device package which is sufficient for its intended purpose, durable enough to withstand the abuses expected in the operating environment, and one which is configured to permit integrity testing at an intermediate point in the assembly of such devices.
An electronic device 20 is shown in FIGS. 1 and 2. Device 20 includes a flexible circuit substrate 22 upon which various electronic components have been mounted. In the illustrated example, device 20 is configured as a battery-powered communication device which is suitable for use as an RF communication device. Accordingly, device 20 includes an antenna 24 supported over substrate 22, a thin-profile battery 26 (FIG. 1) mounted on the substrate, and an integrated circuitry chip 28 configured for RF operation. An exemplary device and/or chip is shown and described in U.S. patent application Ser. No. 08/705,043, which names James O'Toole, John R. Tuttle, Mark E. Tuttle, Tyler Lowrey, Kevin Devereaux, George Pax, Brian Higgins, Shu-Sun Yu, David Ovard and Robert Rotzoll as inventors, which was filed on Aug. 29, 1996, is assigned to the assignee of this patent application, and which is incorporated by reference herein.
One challenge in producing a device such as device 20 relates to mounting the electronic components on the substrate; in particular, mounting battery 26 suitably on substrate 22 such that not only are desirable electrical connections made between electronic componentry and the battery, but the battery is sufficiently physically fixed over the substrate so that it does not become inadvertently dislodged. In addition, once electronic components are mounted on the substrate and before further processing, it is desirable to test or otherwise determine if the appropriate electrical connections have been made between the various components.
Referring to FIGS. 2 and 3, device 20 is shown prior to battery 26 being mounted thereon. Dashed line 30 in FIG. 2 depicts an outer perimeter of battery 26, were it to be mounted on the substrate. Shown generally at 32 and within perimeter 30 is a conductive contact s node pattern which, heretofore, has been utilized to form an electrical and mechanical connection with a thin-profile battery such as battery 26. The contact node pattern can be formed from a suitable conductive printed or screened-on ink such as silver printed thick film ink. Typically, such electrical and mechanical connection is formed through the application of a suitable conductive epoxy over the pattern, with the battery being subsequently bonded into place. When the battery is bonded into place, the contact node pattern is not directly accessible for verifying electrical connection with the battery.
Typically, a battery is bonded with the substrate as shown in FIGS. 3 and 4. One type of substrate which has been found suitable for use with electronic devices of the type described above includes a temporary carrier substrate 36 having a thin polyester substrate 38 bonded therewith. Conductive epoxy 34 is formed over each of the depicted node portions (not specifically designated). Battery 26 (FIG. 4) is placed into abutting contact with the epoxy (and node portions) such that a suitable bond is formed between a terminal housing member of the battery (not specifically designated) and the node portions over which the conductive epoxy was formed. The epoxy is subsequently cured into place, if necessary, and the substrate undergoes subsequent processing to provide a finished device.
It is desirable in some instances to encapsulate or otherwise fortify electronic devices for a number of different reasons. Encapsulant material, such as material 40 in FIG. 5, can increase the useful lifetime of the device by protecting the individual electronic components from outside influences. Encapsulant material can provide an added degree of support so that mounted components are not undesirably shifted or otherwise moved over the substrate once mounted thereon. It is also desirable, prior to encapsulating the devices, to test the devices for the integrity of the electrical connections made between the various electronic components thereon. Once the components, and in particular the battery, have been mounted on the substrate, however, it is difficult to suitably test or probe the electrical connection with the substrate because such connections are usually blocked by the components.
This invention arose out of concerns associated with providing improved apparatuses and methods for mounting and testing electronic components over substrates. This invention also arose out of concerns associated with providing improved electronic devices.